is funded by the SNSF and the DFG in the framework of the CSCS research unit. In grass leaves, stomatal rows always form next to leaf veins, suggesting that this spatial coordination is important for water supply and demand (Baird & Raissig (2026) Ann Rev Plant Biol Ann Rev Plant Biol). Yet how the development of veins and stomata is spatially coordinated remains an open question. Building on a single-cell atlas of g…